Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
Note: This feature is only available in Dedicated Web Workers.
The VideoTrackGenerator interface of the Insertable Streams for MediaStreamTrack API has a WritableStream property that acts as a MediaStreamTrack source, by consuming a stream of VideoFrames as input.
VideoTrackGenerator() Creates a new VideoTrackGenerator object which accepts VideoFrame objects.
VideoTrackGenerator.muted A Boolean property to temporarily halt or resume the generation of video frames in the output track.
VideoTrackGenerator.track The output MediaStreamTrack.
VideoTrackGenerator.writable The input WritableStream.
The following example is from the article Unbundling MediaStreamTrackProcessor and VideoTrackGenerator. It transfers a camera MediaStreamTrack to a worker for processing. The worker creates a pipeline that applies a sepia tone filter to the video frames and mirrors them. The pipeline culminates in a VideoTrackGenerator whose MediaStreamTrack is transferred back and played. The media now flows in real time through the transform off the main thread.
const stream = await navigator.mediaDevices.getUserMedia({ video: true });
const [track] = stream.getVideoTracks();
const worker = new Worker("worker.js");
worker.postMessage({ track }, [track]);
const { data } = await new Promise((r) => {
worker.onmessage = r;
});
video.srcObject = new MediaStream([data.track]);worker.js:
onmessage = async ({ data: { track } }) => {
const vtg = new VideoTrackGenerator();
self.postMessage({ track: vtg.track }, [vtg.track]);
const { readable } = new MediaStreamTrackProcessor({ track });
await readable
.pipeThrough(new TransformStream({ transform }))
.pipeTo(vtg.writable);
};